hdWalletFromXprv() and getSignerForAddress() for xprv type were deriving
addresses directly from the root key (m/N) instead of the standard BIP44
Ethereum path (m/44'/60'/0'/0/N). This caused imported xprv wallets to
generate completely wrong addresses.
Navigate to the BIP44 Ethereum derivation path before deriving child
addresses, matching the behavior of mnemonic-based wallet imports.
Add the ability to import an existing HD wallet using an extended
private key (xprv) instead of a mnemonic phrase.
- New 'xprv' wallet type with full HD derivation and address scanning
- New importXprv view with password encryption
- Updated getSignerForAddress to handle xprv wallet type
- Added xprv link to the add-wallet view
- Allow adding derived addresses for xprv wallets
Closes#20
